Estimating the Timing of Long Bone Fractures: Correlation Between the Postmortem Interval, Bone Moisture Content, and Blunt Force Trauma Fracture Characteristics

• NCJ Number: 224709
• Journal: Journal of Forensic Sciences Volume: 53 Issue: 5 Dated: September 2008 Pages: 1028-1034
• Author(s): Danielle A.M. Wieberg M.A.; Daniel J. Wescott Ph.D.
• Date Published: September 2008
• Length: 7 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

Given limited existing knowledge about how long perimortem long-bone fractures persist into the postmortem interval (PMI), this study used 60 pig long bones in determining the correlation between the postmortem interval, bone moisture content, and the characteristics of blunt-force trauma fracture.

Abstract

The study generally found a continuous transition in fracture characteristics associated with time after death. Fracture appearance changed from fractures with predominately smooth surfaces, obtuse or acute angles, and curved or V-shaped outlines to fractures with jagged surfaces, more right angles, and fewer curved or V-shaped outlines over 5 months. As a result of these changes, bones fractured near death are apparently detectable as perimortem, and bones fractured 5 months after death have clear dry-bone fracture characteristics; however, bones fractured between the two terminal intervals present significant ambiguity in terms of determining the timing of the injury. Bones fractured 28 days after death are almost indistinguishable from those fractured just before death. Bones broken 57-113 days after death often exhibit both perimortem and postmortem characteristics. The results indicate that bones do not consistently show clear postmortem characteristics until 141 days after death. Since bones retain fresh-bone properties long after death and these properties are associated with perimortem fractures, caution should be used when determining the timing of the fracture. The 60 long bones were exposed to natural taphonomic conditions and fractured with a steel bone-breaking apparatus every 28 days throughout a 141-day period. Differences between macroscopic blunt-force trauma fracture characteristics (fracture angle, surface morphology, and outline) were examined in order to determine whether they varied over time or in relationship to bone moisture content (ash weight) and overall assessment. 5 tables, 2 figures, and 22 references